1. Field of the Invention
The present invention relates to an improved fish processing apparatus that removes the skin from each of a plurality of conveyed fish bodies that are transported to blade members adjustably and movably supported by a supporting frame. The frame carries arms that have blade members at their distal ends, the blades being movable about a pivot to allow the scraping edge of each blade to move slightly side-to-side as the blade engages differing contours presented by the fish body during processing.
2. General Background
In the processing of fish such as tuna, undesirable skin and scales must be separated from the edible parts. In the processing of fish such as tuna, it is common to freeze a catch of fish at sea and to process the catch on shore. The processing normally involves thawing the fish followed by manual operations of slicing the fish belly and the removal of viscera. The visceral cavity is then washed with water and the tuna is inspected for spoilage. The tuna is then usually cooked whole in a batch type precooking operation.
Manual prior art methods of processing tuna are described in greater detail in U.S. Pat. No. 3,594,191 issued to J. M. Lapeyre. The '191 Lapeyre patent discloses the concept of cutting the tuna in lateral sections at spaced intervals and thereafter separating the edible loin portions to provide discrete cannable portions.
A later U.S. Pat. No. 3,593,370 entitled "Method of Butchering Tuna" issued to J. M. Lapeyre, describes a method for processing such transverse tuna sections while frozen. The method of butchering frozen tuna described in the '370 Lapeyre patent includes the subdivision of the whole fish into a plurality of transverse cross-sections and subsequently subdividing the cross-sections into frozen segments. The junctures between the segments are along lines generally parallel to the longitudinal axis of the fish and to the backbone thereof. Each lateral fish section is skinned and the skinned sections operated on to effect a separation of the scrap parts of the segments from the loin meat parts, while the latter were still in at least a partially frozen condition.
U.S. Pat. No. 3,800,363 issued to J. M. Lapeyre entitled "Tuna Butchering Method and System" describes an automated butchering method and system for separating the edible loin portions of transverse tuna slices provided by subdivision of a frozen whole tuna.
Three additional, more recently issued U.S. Patents that are owned by The Laitram Corporation, assignee of the present application, and relate to transverse fish section processing and water jet cutters include U.S. Pat. No. 4,748,724, entitled "Support Apparatus For Use In Video Imaging And Processing Of Transverse Fish Sections; U.S. Pat. No. Re. 33,917, entitled "Support Apparatus For Use In Video Imaging And Processing Of Transverse Fish Sections;" and U.S. Pat. No. 5,181,879 entitled "Method and Apparatus for Processing Fish Into Transverse Sections."
Patents have issued which relate to the problem of removing skin from fish that are to be processed. One recently issued U.S. Pat. No. 5,135,432 entitled "Method of and Machine for Cutting Nape Muscles from a Front Part of a Fish and Removing the Skin From the Nape Muscle" is issued to S. Kristinsson. The Kristinsson '432 patent discloses a method and a machine for cutting a nape muscle of a fish from the front part of a fish, after the fish has been parted, and removing the fish skin from the nape muscle. The method includes moving the front part along a fixed straight track to and past vertical circular knives which cut vertical cuts at each side of the spinal crest and at the same time to and past horizontal fixed knife blade edges, fixed on the leading portion of a plough structure, which in turn is fixed to the shaft mount for the shaft of the circular knives. The plough structure cuts lateral cuts from the spine to the skin, but not through the skin. The outer most side part of the plough structure, the plough spade, is not sharp and is used to tear the nape muscle from the attached skin, when the skin is pulled forward through a gap formed between the plough spade and a sliding table below the plough structure, the nape muscle being retained at the upper surface of the plough structure. The machine delivers the nape muscles without bones and without skin.
A fish skinner is disclosed in U.S. Pat. No. 5,184,973. The '973 patent discloses a process and apparatus for descaling tuna fish and the like wherein the fish is a least partially cooked and then cooled to a back bone temperature of about seventy to one hundred (70.degree. F. to 100.degree. F.) degrees Fahrenheit. The fish is placed on a conveyor and passed through horizontally and vertically disposed brushes. Jets of water are sprayed on the fish at the point of contact of the fish and the brushes to thereby wash away the scales and skin as removed by the brushes.
Another fish skinner patent is disclosed in U.S. Pat. No. 5,197,916. The '916 patent discloses a process and apparatus for skinning fish, particularly tuna fish which comprises passing a precooked fish body along conveyor belt means and the like while a series of rotating brushes above one side of and adjacent to the belly and back of the fish scrape the skin from those parts of the fish, passing the fish on the conveyor belt to a wheel around which the belt passes while a second belt contacts the opposite side of the fish and also passes around the wheel to hold the fish intact on the wheel until the fish is half way around the wheel and is turned over, depositing the turned over fish onto a third conveyor belt that receives the fish with the unscraped side thereof in the upper position, subjecting the unscraped side of the fish, and optionally, the belly and back thereof, to the rotating brushes to remove substantially all of the skin from the fish, and simultaneously spraying streams of water on the fish passing thereunder and the belts while removing skin from the fish and reducing deposit of the debris therefrom on the abrading apparatus.